DevTools error page origin

Describe the bug

After http://localhost:5173/__devtools/embedded.js is mounted, the DevTools trying to reach assets from Spring Boot server (localhost:8080), instead of Vite server, where DevTools assets are actually served (localhost:5173).

Reproduction

Copy it, start Spring Boot and vite dev: https://github.com/elec7reify/dummy

System Info

OS: Windows 11 10.0.26200
    CPU: (16) x64 AMD Ryzen 7 7840HS w/ Radeon 780M Graphics     
    Memory: 5.81 GB / 30.65 GB
  Binaries:
    Node: 26.7.0 - C:\Program Files\nodejs\node.EXE
    npm: 11.11.0 - C:\Program Files\nodejs\npm.CMD
    pnpm: 12.1.0 - C:\Users\vb\AppData\Local\pnpm\bin\pnpm.CMD
    bun: 1.4.0 - C:\Users\vb\.bun\bin\bun.EXE
  Browsers:
    Chrome: 153.0.8010.37
    Edge: Chromium (152.0.4191.66)
    Firefox: 155.0.1 - C:\Program Files\Mozilla Firefox\firefox.exe
    Internet Explorer: 11.0.26100.8115

Used Package Manager

pnpm

Validations

• Follow our Code of Conduct
• Read the Contributing Guide.
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
• Check that this is a concrete bug. For Q&A, please open a GitHub Discussion instead.
• The provided reproduction is a minimal reproducible of the bug.

Start by reproducing the problem with the linked dummy project, running Spring Boot and Vite, then inspect the asset URLs used after /__devtools/embedded.js is mounted. Trace why DevTools requests assets from localhost:8080 instead of the Vite server at localhost:5173; done means the DevTools error page and its assets load from the Vite origin.